1. Field of the Invention
The present invention relates to authentication of computer users and services in distributed environments. Particularly, the present invention relates to a Remote Pass-phrase Authentication scheme that provides a way to authenticate users and services using a pass-phrase over a computer network without revealing the pass-phrase.
2. Description of the Related Art
The importance of secure communication is increasing as world-wide networks such as the Internet and the World Wide Web (WWW) portion of the Internet expand. As global networks expand through the interconnection of existing networks, users may gain access to an unprecedented number of services. The services, each of which may be maintained by a different provider, give users access to academic, business, consumer, government, etc. information. Service providers are now able to make their services available to an ever-expanding user base.
The ease with which services and users are able to find each other and the convenience associated with on-line transactions is leading to all increase in the number of remote business and related transactions. However, users and services are not always certain who or what is at the other end of a transaction. Therefore, before they engage in business and other transactions, users and services want and need reassurance that each entity with whom they communicate is who or what it purports to be. For example, users will not be willing to make on-line purchases that require them to reveal their credit card numbers unless they are confident that the service with which they are communicating is in fact the service they wanted to access. Commercial and other private entities who provide on-line services may be more reluctant than individuals to conduct business on-line unless they are confident the communication is with the desired individual or service.
Both users and services need reassurance that neither will compromise the integrity of the other nor that confidential information will be revealed unintentionally to third parties while communications are occurring. Security in a global network, however, may be difficult to achieve for several reasons. First, the connections between remote users and services are dynamic. With the use of portable devices, users may change their remote physical locations frequently. The individual networks that comprise the global networks have many entry and exit points. Also, packet switching techniques used in global networks result in numerous dynamic paths that are established between participating entities in order to achieve reliable communication between two parties. Finally, communication is often accomplished via inherently insecure facilities such as the public telephone network and many private communication facilities. Secure communication is difficult to achieve in such distributed environments because security breaches may occur at the remote user's site, at the service computer site, or along the communication link. Consequently, reliable two-way authentication of users and the services is essential for achieving security in a distributed environment.
Two-way authentication schemes generally involve handshaking techniques so that each party may verify he or she is in communication with the desired party regardless of each party's location or the types of devices in use. The problem to be solved is one in which a user communicates with a service that wishes to learn and authenticate the user's identity and vice versa. To clarify the problem, there are three aspects of network security that may be distinguished:
______________________________________ Identification: the way in which a user or service is referenced. Authentication: the way in which a user may prove his or her identity. Authorization: a method for determining what a given user may do. The same aspects apply to services as well as users. ______________________________________